Account page improvements, including custom validator, extension hook
Unblocked checkout page requirements.
Various other improvements.

git-svn-id: https://silverstripe-ecommerce.googlecode.com/svn/branches/burnbright_dbcart@270 950b781c-c544-efab-2f99-90083ee69683
delete for products in model admin

git-svn-id: https://silverstripe-ecommerce.googlecode.com/svn/branches/burnbright_dbcart@273 950b781c-c544-efab-2f99-90083ee69683
removed debug code

git-svn-id: https://silverstripe-ecommerce.googlecode.com/svn/branches/burnbright_dbcart@287 950b781c-c544-efab-2f99-90083ee69683
fixed up support for setting cart quantity

git-svn-id: https://silverstripe-ecommerce.googlecode.com/svn/branches/burnbright_dbcart@289 950b781c-c544-efab-2f99-90083ee69683